correlogram {spatial} | R Documentation

## Compute Spatial Correlograms

### Description

Compute spatial correlograms of spatial data or residuals.

### Usage

    correlogram(krig, nint, plotit = TRUE,  ...)

### Arguments

`krig` | trend-surface or kriging object with columns `x`, `y`, and `z`
`nint` | number of bins used
`plotit` | logical for plotting
`...` | parameters for the plot

### Details

Divides range of data into `nint` bins, and computes the covariance for pairs with separation in each bin, then divides by the variance. Returns results for bins with 6 or more pairs.

### Value

`x` and `y` coordinates of the correlogram, and `cnt`, the number of pairs averaged per bin.

### Side Effects

Plots the correlogram if `plotit = TRUE`.

### References

Ripley, B. D. (1981) Spatial Statistics. Wiley.

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.

### See Also

`variogram`

### Examples

    data(topo, package="MASS")
    topo.kr <- surf.ls(2, topo)
    correlogram(topo.kr, 25)
    d <- seq(0, 7, 0.1)
    lines(d, expcov(d, 0.7))

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